Module: Channel Network
(c) 2001 by O.Conrad
Menu: Terrain Analysis > Channels
Description
This module derives a channel network based on gridded digital elevation data.
Use the initiation options to determine under which conditions channels shall start.


Parameters
NameTypeIdentifierDescriptionConstraints
Input
Elevation Grid (input)ELEVATIONA grid that contains elevation data.
Flow Direction (*)Grid (optional input)SINKROUTEAn optional grid that provides information about flow directions.
Values between 1 to 8 force the flow of a cell to be given to one its adjacent neighbor cells (1->NE, 2->E, 3->SE, 4->S, 5->SW, 6->W, 7->NW, 8->N). In case of other values the algorithm will use its own routing scheme.
This option is in particular useful to supply the algorithm with routes that lead the flow through closed depression.
Initiation Grid Grid (input)INIT_GRIDDependent on the chosen 'Initiation Type' and 'Initiation Threshold' the values of this grid control where a channel is initiated.
Divergence (*)Grid (optional input)DIV_GRIDTracing: Convergence
Tracing: Weight (*)Grid (optional input)TRACE_WEIGHTTracing: Weight
Output
Channel NetworkGrid (output)CHNLNTWRKIf a cell is part of a channel its value equals the channel order. Otherwise the cell is marked as no-data.
Channel DirectionGrid (output)CHNLROUTEIf a cell is part of a channel then its value shows the flow direction of the channel (1->NE, 2->E, 3->SE, 4->S, 5->SW, 6->W, 7->NW, 8->N). Otherwise the cell is marked as no-data.
Channel NetworkShapes (output)SHAPESThis shapes layer will contain the resulting channel network in vector format (lines).
Options
Initiation TypeChoiceINIT_METHODOptions:
- Less than
- Equals
- Greater than
Controls under which condition a channel is initiated.
Available Choices:
[0] Less than
[1] Equals
[2] Greater than
Initiation ThresholdFloating pointINIT_VALUEDependent on the chosen 'Initiation Grid' and 'Initiation Type' this value controls under which condition a channel is initiated.
Tracing: Max. DivergenceIntegerDIV_CELLSTracing: Stop after x cells with divergent flowMinimum: 1.000000
Min. Segment LengthIntegerMINLENMinimum Segment Length (Cells)
(*) optional